The present invention relates to a sheet feeding device for a copier, facsimile transceiver, printer or similar image forming equipment.
A sheet feeding device capable of accommodating a great amount of sheets at a time has been proposed in various forms in the past. For example, Japanese Utility Model Laid-Open Publication No. 182748/1982 discloses a sheet feeding device to be loaded with a single stack of sheets. Japanese Patent Laid-Open Publication No. 33638/1974 proposes a device elaborated for supplementing sheets. Further, Japanese Patent Publication Nos. 58090/1989 and 58091/1989 each teaches a sheet shifting device which is so constructed and arranged as to accommodate a great amount of sheets in two stacks to thereby reduce the overall thickness thereof.
A drawback with the device disclosed in the above-mentioned Japanese Utility Model Laid-Open Publication is that the vertical dimension thereof has to be great enough to accommodate a great amount of sheets in a single stack. This kind of device, therefore, cannot be incorporated in an equipment body and needs an extra and substantial space for installation at the side of the equipment body. Another drawback is that to supplement sheets the operator has to interrupt the sheet feeding operation of the device and then lower an elevator tray to obtain a space for a supplement, i.e., the device cannot effect continuous sheet feed and lacks in productivity. The devices taught in the above-mentioned Japanese Patent Laid-Open Publication and Patent Publications each shifts, when one of two stacks of sheets is fully fed out, the other stack of sheets in an intended direction of sheet feed to allow the operator to place another stack of sheets in the unoccupied space. Such a device can effect continuous sheet feed and, therefore, enhances productivity. However, since this kind of device implements a support for loading a sheet stack as belts, pressing mean or similar sheet shifting means mounted on an equipment body, the operator intending to set a sheet stack in the device has to insert it as far as the sheet shifting means, resulting in troublesome and inefficient sheet supply.